Mersana grabs a $792M ADC development pact with Merck KGaA

Mersana Therapeutics has inked another antibody-drug conjugate development pact, this time with the R&D team at Merck KGaA in Germany.

The Cambridge, MA-based biotech reported this morning that Merck KGaA will offer up some antibodies for use in ADCs, in which an antibody homes in on cancer cells to deliver highly toxic and targeted drugs. There were no numbers in the statement, but a spokesperson for the company says that the package includes $792 million in upfront and potential milestone payments. There was no breakout in the upfront, though discovery deals like this are typically heavily back-ended with biobucks.

Mersana has already partnered its Fleximer platform with Endo. Adimab and more recently Takeda, which forged a deal just weeks ago. The 2012 Fierce 15 company has been working with technology developed by Mikhail "Misha" Papisov at Massachusetts General Hospital and was originally seeded by PureTech about a decade ago. The secret sauce behind Mersana's technology revolves around the use of its linker with a polymer backbone, which Mersana Chief Business Officer Eva Jack says is "highly soluble, so we can add more toxin to our polymer."

At the beginning of the year NEA partner David Mott--the former CEO of MedImmune--took over at Mersana as executive chairman as Nicholas Bacopoulos returned to his role as a board member after a stint as CEO.

Merck KGaA is jumping into a field pioneered by the likes of Seattle Genetics and Roche/Genentech. Over the past few years the German pharma company has been struggling to reorganize its R&D division after some notable failures in the clinic. In this deal the company will leave the discovery work to Mersana and then take on clinical development of any drug candidates that make the cut.

Jack says Mersana now has 29 staffers and is also working on its own pipeline as well as more potential partnerships in the ADC field.

"This new collaboration provides an exciting opportunity to expand our oncology drug discovery and development portfolio into the evolving ADC space," said Dr. Andree Blaukat, head of Merck Serono's Translational Innovation Platform Oncology in Darmstadt, Germany, in a statement. "We have a long-standing commitment to improving oncology care, and we aim to deliver the best benefit possible to patients. Partnering with Mersana allows us to incorporate cutting-edge research and technical excellence to enrich our pipeline."